Polymeric substances are known which are capable of absorbing several times their own weight of water, whereupon they are transformed into gel. These hydrophilic polymers are either natural or semi-synthetic polymers, such as derivatives of cellulose, starch, alginate, polysaccharides, or synthetic polymers based, in particular, on maleic acid or (meth)acrylic acid.
Therefore, a wide variety of hydrophilic polymers are known but for agricultural, horticultural or medical use it is still being endeavoured to find products which have a high absorption capacity not only for water but also for water charged with electrolytes, with a rapid absorption rate and satisfactory retention capacity in the state of a gel. Moreover, for hygienic applications, in particular in the production of articles intended to be brought into contact, while in a moist condition, with the human epidermis, it is endeavoured to find atoxic products which are inexpensive, which are not subject to syneresis and which contain neither nitrogenous derivatives nor residual monomers. It is fact that at present none of these known hydrophilic polymers meets the particular market requirements.